The present invention relates generally to medical devices and more particularly to medical devices for performing an anterior capsulotomy (capsulorrhexis).
During cataract surgery, or removal and replacement of the natural lens of the eye, a surgeon must enter the globe, using a small millimeter blade, to access the cataract, which commonly involves the centermost layer (the cortex) of the lens. Most often, a clear corneal suture-less incision of 3 mm or less is made. The anterior chamber is then filled with a viscoelastic substance to protect the cornea during cataract surgery and to maintain the integrity of the anterior chamber when necessary. An additional incision called a paracentesis is placed at approximately 90° (ninety degrees) to facilitate the manipulation of the cataract during phaco emulsification, a process that utilizes ultrasound to gently suction out the cataract.
Prior to the suctioning of the cataract, an opening in the capsule is needed to allow for the use of devices required to effectively remove cortex and mucleus from the capsule. It is of the utmost importance that the integrity of the anterior (after anterior capsulotomy) and posterior capsule is maintained. Post-operatively the capsular envelope serves as a retainer for an artificial implant (intra-ocular lens (IOL). Without the capsule, or if the structure is compromised, the use of a posterior implant may be contraindicted since the capsule provides the support needed to keep the artificial lens in place.
There are two prior art methods of performing an anterior capsulotomy. The first, referred to as the “can opener” technique, is an older procedure before more modern techniques and advanced equipment (such as the Utrata forceps) became available. This procedure involves the surgeon making a series of small, connected punctures using a cystotome, or bent needle, running 360° (three-hundred and sixty degrees) around the anterior portion of the capsule, resulting in an opening that resembles the appearance of the top of an open can.
The second method requires the surgeon to nick the anterior portion of the capsule with a cystotome to create a tear in the membrane. Using an Utrata forceps, an edge of the tear is grasped and guided to create a circular aperture in the surface of the anterior capsule.
Both techniques require significant skill on the part of the surgeon and generally take years to master. Even a slight error, can result in a devastating prognosis for the patient. If the capsulotomy is too small, the cataract may not be removed sufficiently, If the capsulotomy is too large or the anterior capsule tears during the process, extending and resulting in a posterior capsular tear, the capsule may not be able to support the artificial lens implant or, worse yet, there may be a loss of the vitreous. If a vitreous loss occurs an immediate vitrectomy is required, which has the potential of a lifetime of visual impairment or blindness for the patient. Furthermore, the use of many newer intraocular lenses require that the anterior capsulotomy be performed such that a circular opening with a predetermined diameter be made.
Thus, the prior art methods for performing anterior capsulotomies possess inherent deficiencies that increase the likelihood of complications and decrease the procedure's safety. Therefore, there is a need for a means of reliably and safely performing an anterior capsulotomy.